resourceCollector.js
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"use strict";
/**
* Copyright 2020 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.ResourceCollector = void 0;
/**
* ResourceCollector class implements asynchronous logic of calling the API call that supports pagination,
* page by page, collecting all resources (up to `maxResults`) in the array.
*
* Usage:
* const resourceCollector = new ResourceCollector(apiCall, maxResults); // -1 for unlimited
* resourceCollector.processAllPages(request).then(resources => ...);
*/
class ResourceCollector {
constructor(apiCall, maxResults = -1) {
this.apiCall = apiCall;
this.resources = [];
this.maxResults = maxResults;
}
callback(err, resources, nextPageRequest) {
if (err) {
// Something went wrong with this request - failing everything
this.rejectCallback(err);
return;
}
// Process one page
for (const resource of resources) {
this.resources.push(resource);
if (this.resources.length === this.maxResults) {
nextPageRequest = null;
break;
}
}
// All done?
if (!nextPageRequest) {
this.resolveCallback(this.resources);
return;
}
// Schedule the next call
const callback = (...args) => this.callback(...args);
setImmediate(this.apiCall, nextPageRequest, callback);
}
processAllPages(firstRequest) {
return new Promise((resolve, reject) => {
this.resolveCallback = resolve;
this.rejectCallback = reject;
// Schedule the first call
const callback = (...args) => this.callback(...args);
setImmediate(this.apiCall, firstRequest, callback);
});
}
}
exports.ResourceCollector = ResourceCollector;
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